American Airlines flight attendants are getting a 1.6 percent raise after an arbitrator ruled in an ongoing pay dispute Tuesday. That’s far less than the 8.2 percent the union had requested, prompting its president to call the raise “insulting.”

“Flight attendants at this airline deserve industry-leading compensation. American CEO Doug Parker had an opportunity to deliver on the promise he made to make his employees the best-paid in the industry, and he refused,” Bob Ross, president of the Association of Professional Flight Attendants, said in a statement.

The dispute traces back to the complicated contract negotiations to bring together flight attendants from US Airways and American Airlines after the two carriers merged.

Executives at the newly merged company promised industry-leading contracts for its labor groups, but at the time American struck a deal with flight attendants in late 2014, United was in the midst of negotiations with its own flight attendants.

American’s deal included a clause that allowed for the two sides to revisit the pay scale once United reached a new contract with its flight attendants, which was approved in August.

As American and the union revisited the contract, the union began pushing for its pay adjustment to reflect a six percent raise given to Delta flight attendants in November, as well as the new United deal.

But American pushed back and held that only United’s new contract should be considered, not Delta’s recent raises, significantly lowering the size of the raise due to American’s more than 25,000 flight attendants.

The average American flight attendant made $48,918 in 2015, according to the most recent data available from the Massachusetts Institute of Technology’s Airline Data Project.

With neither side willing to budge, the case ended up in arbitration where an arbitrator issued a binding ruling Tuesday in favor of American Airlines’ position.

In a memo to flight attendants Tuesday, American said it disagreed with the union on the size of the pay raise due and agreed to arbitration to “make sure it was the accurate number.”

The company said that since last April, flight attendants have seen a 9.6 percent increase in pay, including the 1.6 percent awarded by the arbitrator. Flight attendants will also receive back pay reflecting the 1.6 percent increase going back to Sept. 1, 2016.

The ruling comes as issues of pay simmer at another of American’s largest employee groups. The company’s pilots have seen their peers at other carriers strike richer deals in recent years, prompting their union to call for a mid-contract adjustment to bring pay more in line with competitors. But American has insisted it won’t revisit the issue until the contract expires in 2020.

American did reinstate company-wide profit sharing in 2016, but at a lower percentage of total profits than rivals.